What is Mylar?

Mylar is a polyester film (similar to a plastic sheet) made from stretched polyethylene terephthalate. Polyethylene terephthalate (PET) is the most common thermoplastic polymer resin of the polyester family. “Thermo,” as in heat, which is why home inspectors, we nor typically find these types of plastics and films in the laundry room being used as dryer vent hoses. 

The Mylar vents in the diagram below are common, but what is also common is their misuse. There are several types of vent systems in a house, including your dryer, your water heater (if it uses gas), and your exhaust fans in the bathroom. These appliances or areas are heat-producing and thus need a safe means of expelling heat to the exterior of the home. This is when having the proper Mylar vent in place matters most.

Whether your dryer is electric or gas, it will most likely have a means of exhaust. This exhaust pipe/hose needs to be able to handle the amount of heat coming out of your dryer. Appliances are capable of reaching over 100ºF, and unfortunately not all Mylar vents can take the heat. Based on their composition some vents are labelled combustible, meaning a hot appliance can become a potential safety hazard. 

Home inspectors examine these before a closing or when a home is first put on the market, however it is definitely in the homeowner’s best interest to ensure they have the right system in place regardless if they’re preparing to sell. 

Below are types of vents Hope Home Inspections suggests for your appliances. 

Gas/Electric Appliances: 

• Flex duct: Semi-rigid metal flexible dryer duct, made of aluminum (lighter, less costly, easily bent and damaged if not handled carefully) or steel (a bit heavier, more resistant to kinks, crushing, dents during installation).
  
• Solid metal rigid dryer duct, aluminum; functional, modest cost, easy to handle, but requires use of elbows to make bends handled by flex duct installations. Smooth surfaces of solid metal duct work slow lint accumulation.

  
Bathroom Venting: 

• Flex-duct: Plastic and wire flexible dryer vent duct a coil of spring wire covered with a thin, usually white, plastic. Although we have observed this material widely used in homes as "dryer vent ducting" it should not be used for that purpose.